In some long horizontal completions steps are taken to reduce the tendency of produced fluids to run along the outside of screens until reaching a necking down of the annular space outside the screened interval before making an attempt to go through the screen, usually on the uphole or heel end of the screen interval. To counteract this effect, the screen sections are provided with a non-perforated base pipe under the screen section that forces the fluid along an annular path between the base pipe and the screen until a restriction section is reached. The restriction section can be a spiral path that provides a flow restriction to the filtered fluid. After going through the spiral restriction section, the filtered fluid reaches the openings to go though the base pipe. This product is offered by Baker Oil Tools under the product name Equalizer Screen. A series of screens with the same or differing restrictions are arranged in an interval to distribute the incoming flow among all the screen sections by counteracting the tendency of the fluid to otherwise follow the path of least resistance and flow in the annular space outside all the screen sections until reaching the heel of a horizontal run and trying to go through the most uphole screen first.
It is desirable for a variety of reasons to keep the inflow openings in such screens closed until the screens are to be put in service. For one thing, if the inflow openings are kept closed there is no flow through the screens until they are to be put into service. Additionally, with the base pipe closed it can be pressurized so that equipment mounted on the lower end such as a mud motor to drive a bit can be installed and operated to bring the screens into the desired generally horizontal open hole completion for production. Additionally, hydraulic-set packers in the screen liner can be set without resorting to a wash pipe or inner string to isolate the packer inlet from what would otherwise be an open area at the screens.
While a possible solution is to plug the inflow openings with a rupture disc, the problem with that is that there is no assurance all the rupture discs will break at the same time. If even one rupture disc breaks early, the others will not break at all as all the developed pressure within the base pipes will dissipate through the opened rupture disc. Early attempts to deal with this issue can be seen in U.S. Pat. No. 5,425,424 and the cited patents therein to Zandmer.
What is needed is a technique that keeps the inflow passage closed until the screens need to be put into service while ensuring that all the screens will go into service when needed because the openings will go to the open position when needed.
The present invention relates to a valve design for the inflow openings in the screen sections that make up the screened interval that keep the screens closed for run in to prevent flow through them while at the same time allowing pressure to build up within the base pipes so that tools can be operated. When the applied pressure is relieved the valves can open so that the screens can become operative. These and other features of the present invention will be more readily appreciated by those skilled in the art from a review of the description of the preferred embodiment and the associated drawings with the understand that the full scope of the invention is indicated in the claims.